The present invention relates to an apparatus for recording and/or reproducing information by reciprocating an information recording medium relative to a recording/reproducing head and, more particularly, to a card carrier mechanism for stably reciprocating a card-like information recording medium.
The form of the information recording medium may be of a disk-like medium (e.g., a magnetic disk, an optical disk, and a magneto-optical disk), a tape-like medium (e.g., a magnetic tape and an optical tape), or a card-like medium (e.g., a magnetic card and an optical card). Among these media, the card-like information recording medium (to be referred to as a card hereinafter) has been popular due to its easy access, easy fabrication, and portability. In particular, an optical card can be used in high-density recording, and extensive studies thereon has been made in recent years. An optical card will be exemplified below.
A conventional information recording/reproducing apparatus using such a card scans data tracks in the card by reciprocating the card relative to a recording/reproducing head to achieve information recording/reproduction.
FIG. 1A is a perspective view of a card drive mechanism in a conventional information recording/reproducing apparatus, FIG. 1B is a schematic sectional view of the apparatus taken along a direction of arrow A thereof, and FIG. 1C is a schematic sectional view of a card insertion portion.
An optical card 1 has a recording area 2, and information is recorded as a pit train in the recording area 2. The pit trains are defined as information tracks 3, respectively. Each information track 3 is scanned to reproduce information. Information recording/reproduction can be performed by using an optical beam 34 from a head 4.
The optical card 1 is clamped between drive rollers 5a, 5b, and 5c and press rollers 6a, 6b, and 6c and can reciprocate along directions of the double-headed arrow B. For illustrative convenience, the drive roller 5a and the press roller 6a constitute a roller pair a; the rollers 5b and 6b, a roller pair b; and the rollers 5c and 6c, a roller pair c.
The press rollers 6a, 6b and 6c are, rotatably supported by a connecting plate 7. Both ends of the connecting plates 7 are connected to a frame 9 through springs 8a and 8b as biasing means. The press rollers 6a, 6b, and 6c are biased by the springs 8a and 8b to press the drive rollers 5a, 5b, and 5c respectively.
The rotating shafts of the drive rollers 5a, 5b, and 5c rotatably extend through the frame 9. Pulleys 10a, 10b, and 10c are fixed on the rotating shafts, respectively. A rotational force of a motor 11 is transmitted to the pulleys 10a, 10b, and 10c through a motor pulley 12 and timing belts 13a, 13b, and 13c, so that the drive rollers 5a, 5b, and 5c are rotated.
The nonclamped side of the optical card 1 clamped and reciprocated by the roller pairs a, b, and c is urged by a leaf spring 14, and the clamped side of the optical card 1 abuts against the frame 9. Therefore, the optical card 1 receives the driving force upon rotation of the roller pairs a, b, and c and reciprocates along the frame 9.
The head 4 can be moved at a position corresponding to the roller pair b along directions of double-headed arrow D and emits a light beam onto the recording area 2, as shown in FIG. 1B.
In order to reciprocate the optical card 1, the motor 11 is rotated in the opposite directions. Position sensors 15 and 16 are arranged at two ends of the moving range of the optical card 1 so as to provide the reversing timings. A sensor 18 is arranged near a card insertion portion 17 to detect that the optical card 1 has been inserted therefrom.
As shown in FIG. 1C, a gap t1 in the card insertion portion 17 and a thickness t2 of the optical card 1 satisfy relation t2&lt;t1, and a card having a thickness exceeding a predetermined thickness cannot be inserted in the card insertion portion 17.
In the conventional apparatus described above, since the optical card 1 reciprocates while clamped between the leaf spring 14 and the frame 9, the surface at the nonclamped side of the optical card 1 is deviated in directions (variations in surface level) of double-headed arrow E, as shown in FIG. 1B. For this reason, the distance between the card surface and the head 4 varies. It is thus difficult to always cause a focusing servo circuit to accurately focus the beam from the head 4 onto the optical card 1. As a result, recording and/or reproducing operation is unstable. In the worst case, recording and/or reproduction cannot be performed.
An objective lens in the head 4 may be driven by using an actuator having a wide movable range so as to compensate for the distance variations. However, the control system is complicated, and an expensive actuator must be used. Therefore, the above arrangement does not provide a best solution.